Easy synthesis of new 2-oxo-2,3-dihydro-1H-pyrrolo[1,2-b]pyrazole systems

Citation
Oa. Attanasi et al., Easy synthesis of new 2-oxo-2,3-dihydro-1H-pyrrolo[1,2-b]pyrazole systems, SYNLETT, (7), 2000, pp. 955-958
Citations number
52
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
SYNLETT
ISSN journal
09365214 → ACNP
Issue
7
Year of publication
2000
Pages
955 - 958
Database
ISI
SICI code
0936-5214(200007):7<955:ESON2S>2.0.ZU;2-R
Abstract
1,2-Diaza-1,3-butadienes react with dialkyl 1,3-acetonedicarboxylate in the presence of potassium carbonate to give 2-hydroxy-2,3-dihydro-1H-1-aminopy rroles that in turn produce 1-aminopyrroles by dehydration in the presence of copper(II) trifluoromethansulfonate. The treatment of these compounds wi th sodium hydride leads to NH-substituted 2-oxo-2,3-dihydro-1H-pyrrolo[1,2- b]pyrazole. Under the same reaction conditions, NH-BOC protected 1-aminopyr roles, after acidic cleavage of the BOC protecting group, afford NH-unsubst ituted 2-oxo-2,3-dihydro-1H-pyrrolo[1,2-b]pyrazole.